21495808 has 40 divisors (see below), whose sum is σ = 44040150. Its totient is φ = 10485760.

The previous prime is 21495797. The next prime is 21495809. The reversal of 21495808 is 80859412.

It can be written as a sum of positive squares in only one way, i.e., 21233664 + 262144 = 4608^2 + 512^2 .

It is not an unprimeable number, because it can be changed into a prime (21495809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 524268 + ... + 524308.

Almost surely, 2^21495808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21495808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22020075).

21495808 is an abundant number, since it is smaller than the sum of its proper divisors (22544342).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21495808 is an frugal number, since it uses more digits than its factorization.

21495808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79 (or 43 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 37.

The square root of 21495808 is about 4636.3571907264. The cubic root of 21495808 is about 278.0468150892.

The spelling of 21495808 in words is "twenty-one million, four hundred ninety-five thousand, eight hundred eight".